how to have custom attribute in ConfigurationElementCollection?

Question

for configuration as following

  
  ... other entries
         


        

Answer 1

This may be a bit late but may be helpful to others.

It is possible but with some modification.

• ConfigurationElementCollection inherits ConfigurationElement as such "this[string]" is available in ConfigurationElement.

• Usually when ConfigurationElementCollection is inherited and implemented in another class, the "this[string]" is hidden with "new this[string]".

• One way to get around it is to create another implementation of this[] such as "this[string, string]"

See example below.

public class CustomCollection : ConfigurationElementCollection
{
    protected override ConfigurationElement CreateNewElement()
    {
        return new CustomElement();
    }

    protected override object GetElementKey(ConfigurationElement element)
    {
        return ((CustomElement)element).Name;
    }

    public CustomElement this[int index]
    {
        get { return (CustomElement)base.BaseGet(index); }
        set
        {
            if (BaseGet(index) != null)
                BaseRemoveAt(index);

            BaseAdd(index, value);
        }
    }

    // ConfigurationElement this[string] now becomes hidden in child class
    public new CustomElement this[string name]
    {
        get { return (CustomElement)BaseGet(name); }
    }

    // ConfigurationElement this[string] is now exposed
    // however, a value must be entered in second argument for property to be access
    // otherwise "this[string]" will be called and a CustomElement returned instead
    public object this[string name, string str = null]
    {
        get { return base[name]; }
        set { base[name] = value; }
    }
}